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엔티티에 배송, 카테고리 추가

• 주문과 배송은 1:1 (@OneToOne)
• 상품과 카테고리는 N:M (@ManyToMany)

Delivery, Category 엔티티 추가 - ERD

Delivery, Category 엔티티 상세

N:M 관계는 1:N, N:1로 풀어내기

• 테이블의 N:M관계는 중간 테이블을 이용해서 1:N, N:1로 풀어내자
• 실전에서는 중간 테이블이 이렇게 단순하게 생기지는 않음
• @ManyToMany는 제약 : 필드 추가 X, 엔티티 테이블 불일치, 실전 사용 X

Category Entity

package practice;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
public class Category {

    @Id
    @GeneratedValue
    private Long id;

    private String name;

    @ManyToOne
    @JoinColumn(name = "PARENT_ID")
    private Category parent;

    @OneToMany(mappedBy = "parent")
    private List<Category> child = new ArrayList<>();

    @ManyToMany
    @JoinTable(name = "CATEGORY_ITEM",
        joinColumns = @JoinColumn(name = "CATEGORY_ID"),
        inverseJoinColumns = @JoinColumn(name = "ITEM_ID")
    )
    private List<Item> items = new ArrayList<>();

}

Delivery Entity

package practice;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToOne;

@Entity
public class Delivery {

    @Id @GeneratedValue
    private Long id;
    private String city;
    private String street;
    private String zipcode;
    private DeliveryStatus status;

    @OneToOne(mappedBy = "delivery")
    private Order order;
}

// DeliveryStatus 엔티티는 생략

Item Entity

package practice;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
public class Item {

    @Id @GeneratedValue
    @Column(name = "ITEM_ID")
    private Long id;
    private String name;
    private int price;
    private int stockQuantity;

    @ManyToMany(mappedBy = "items")
    private List<Category> categories = new ArrayList<>();

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public int getStockQuantity() {
        return stockQuantity;
    }

    public void setStockQuantity(int stockQuantity) {
        this.stockQuantity = stockQuantity;
    }
}

Member Entity